Remote position marker



Apr1l 7, 1953 R. E. MEAGHER 2634412 REMOTE POSITION MARKER Filed Sept. 14, 1945 2 SI-IEETSSHEET 1 REMOTE SEARCH REPEATER d DETECTOR 20 Lus |2 T0 INTENSIFIER I l l AZIMUTH 33 la AZIMUTH SELSYN SELSYN DIFFERENTIAL T0 SECOND AUXILIARY DETECTOR 44 GATE AMPLIFIER MULTI- VIBRATOR INVENTOR TO SECOND Q RALPH E. MEAGHER AUXILIARY DETECTOR BY LMLLW ATTORNEY April 1953 R. E. MEAGHER REMOTE PQSITION MARKER Filed Sept. 14, 1945 Te CATHODE. RAY TUBE #18.

2 SHEETS-SHEET 2 FIG.3

INVENTOR RALPH E. MEAGHER WLW ATTORNEY Patented Apr. 7, 1953 REMO'IE PGSITION MARKER Navy Applicaton September 14, 1945, Serial No. 616,394

7 Claims. 1

Ihs invention reiates to apparatus for aidin in the aiignment in azimuth and range of a remote object detector with respect to a second object detector, and more particularly to apparatus which produces an illuminated trace on the indicator of the second object detector When the remote object detector is aligned therevvith in azimuth, the length of the trace being an indication of the range setting of the remote object detector.

It is an object of this invention to provide apparatus to aid in the alignment of a remote aux i1iary object detector with respect to another object detector in either azimuth or range or both.

It is a further object of ths invention to provide apparatus to indicate when a remote auxiiary object detector is aligned with respect to another object detector in either azmuth or range or both.

It is a further obiect of ths inventon to provide apparatus to indicate the range setting of a remote auxiliary object detector on the indicator of another object detector or on a repeater indicator of this latter object detector.

It is a further object of this invention to provide apparatus to aid a remote object detector in locating a target detected by another object detector.

Other and further objects wii1 appear during the cour-se of the followng description.

In the use of object detectors, such as those where an electromagnetic wave of high frequency or a supersonic wave is transrnitted and the reflection from an object te be detected picked up on suitable receiving apparatus to give an ndication of the azimuth and range of the object, it is frequently desred to align in azimuth and range a remote auxi1iary object detector with the first detector or With a target detected by the first detector. A case where this situation may arise is on ship board where an object detector used in searchng has located an object in the course of its search, and it is desired t;o train another object detector used in the laying of guns on ths object for use as a target. Gun laying object detectors requre or accuracy very sensitive adjustments of their azimuth and range. According1y, dificuty may be encountered in training this gun laying detector on its target, particularly where great sneed is required. Synchro systems and servomechansms adaptahie for accornplshing such accurate gun laying are descri-bed genera1iy in chapter 12 of Principles of Radar, by the stafi of the M. I. T. Radar School, The Technology Press, Massachusetts Institute of Technology, Cambridge, Massachusetts, 1944.

With the present invention apparatus is pro.- vided vvhich illuminates the plan pcsiton indi-- cator scope of the search object detector, 01 or a repeater of this detector, With a trace wherr thisdetector and a. remote object detector arealigned in azimuth. This trace vvi11 correspond to the azimuth hearing of the search detector. The apparatus of the present invention a1so adjusts the length of ths trace in accordance with the range setting of the auxiliary detector. An operator statoned at the indicator scope of the search 010 ject detector or of its repeater communicates with the operator of the auxiliary detector the correc tions necessary to a1ign the two detectors in azimuth and range.

Reference is now had to the accompanying drawing where:

Fig. 1 is in general a block diagram of the inventon;

Fig. 2 is a circuit diagram showing details of certain portions of Fig. 1; and

Fig. 3 is a view of the sereen of a cathode ray tube under operating conditons.

In the diagram of Fig. 1 a search remote object detector IB transmits a pu1se of high frequency energy from antenna I l rotatabe in azimuth. The refiected energy from a target is picked up by antenna II and after detection is transmitted over path i4 to a remote repeater I9 where it is displayed on cathode ray scopes H and 18 therein. Antenna H is mechanically connected to an azimuth selsyn i3 through linkage i2. The output of this seisyn is transmitted over the ccnventional three wre path l5 to a se1syn in remote repeater |6 to synchronize in azimuth this repeater with antenna l i. It may be noted Wth regard to these selsyns that the conventional two Wi1e power supply has been omitted for purposes of simplification. Thus the energy transmitted over path I4 wi1i appear on scopes I'i and I8 in its proper azimuth and range. Range handwheel [-9 and azirnuth handwheel 20 are used to aid in the reading of the range and azimuth of the data appearing on scopes I! and I8.

A11 auxliary remote object detector 311 is rernotely spaced trom remote repeater |6 andsearch detector iii. Detector is provided as is detector i with an antenna 31 rotatable in azimut'h. An azimuth selsyn 33 is mechanicaliy conneeted to the antenna through linkage 32. Detector is provided wth handvvheels 36 "and which are rotatable to controi the azimuth of antenna 3! and the range setting, respectiveiy.

The output of azimuth selsyn 33 is fed over the conventional three wre path 28 to rotor 38 of difierential selsyn 31. The output of azimuth selsyn |3 is branched from path and fed -to stator 39 of se1syn 31. The shaft of rotor 38 is connected through linirage 26 to a reflegting mirror 40 which rotates in synchronism with the shaft. When the inputs to diierential selsyn 37 are in the same phase relationship, which corresponds to an alignment of antennas |I and 3I in azimuth, the rotor shaft will have a fixed angular position. When the phase relationships are different the shaft assumes an angular position correspondin to the magnitude of this diflerence. Thus the angular position of the shaftis a measure of the phase relationships between the two inputs to the diiierential generator.

A 1ight 4! projects its beam through lens 42 towards mirror 40. With mirror 4!) in one angular position this beam is then reflected to photoelectrio cel] 43. Mirror 49 is angularly adjusted with respect to the shaft of linkage 39 so that the beam of 1ight wi1l fa11 on ce1l 43 When the two inputs to differential selsyn 31 are in the same phase relationship, which occurs When the axes of directivity of antennas l 1 and 31 are aligned in azimuth.

Amplifier 44 and gate multivibrator 45 are genera1ly included within remote repeater I, but are shown as separate blocks for clarity. These are described in more detail in connection with Fie. 2, and their function is only broadly discussed here. A portion of the transmitter pulse of search detector l0 is applied at terminal 55. Photoelectric cel1 43 When rendered oonducting sensitizes an amplifier tube in amplifier 44 to which the transmitter pulse is applied, so that the pulse is passed through the amplifier into gate multivibrator 45. This pulse triggers the multivibrator to produce repetitive rectangular waves (gates) in synchronism with t e transmitter pulse. The duration of each gate is determined b.v certain circuit constante of the multivibrator. This wave is applied over path 41 to the intensifier grid of plan position indicator scope I8 of remote repeater 16 to produce an illuminated radial trace thereon. The trace Wi1l occur on1y When antennas I| and 3! are aligned in azimuth and be of a length de termined by gate multivibrator 45. The anaular position of the trace wil] correspond in azimuth to antenna H. It may be noted that scope [1 is operative to give any desired presentation, for example, the so-called B type where a sector of the azimuth is presented in the horizontal dimension and the range is presented in the vertical dimension.

As previously stated, auxiliary detector 39 is provided with an azimuth handwheel 34 and a range marker handwheel 35. Range handwheel 35 controle a potentiometer 36, which is connected in circuit with other circuit constante of gate multivibrator 48 over path 29. This potentiometer thus controls the length of the radial trace appearing on scope i 8.

When it is desired to align detector 3!) with a target detected by detector lil, which target appears as an arcuate trace on scope l 8, an operator is stationed at remote repeater I 6. A second operator is stationed at the auxiliary detector 39 and controls the azimuth and range setting of this detector by rotating handwheels 34 and. 35, respectively. The first operator at the 1em0te repeater, where the arcuate target trace is visible on scope l8, watches for the radia1 trace to anpear, notes the angular displacement between the radial trace and the target trace, and informs the second operator stationed at the auxiliary de- I8 is visible to the second operator.

tector over suitable communication means of the necessary azimuth adjustment of the auxiliary detector to train it on the target. The range of the target is known to the first operator, it beng the distance of the target trace from the center of scope |8, and the 1ength of the radial trace is an indication of the range setting of the auxiliary detector. It follows that it is only necessary for the iirst operator to inform the second operator of the necessary adjustments of range handwheel 35 to bring the auxiliary detector to proper range, which occurs When the radial trace extends out to the target trace on scope I8. This provides a fast and accurate method of aligning the two detectors in azimuth and range. Remote repeater l6 may be so positioned that scope This eliminates the necessity of the first operator.

It may be desired to direct several auxiliary detectors on the same or different targets as detected by the search detector. This is 1ikely to arise in connection with gun laying whereeach auxiliary detector directs a particular group of guns. A selector switch 27 may be provided in paths 28 and 29 to permit other auxiliary detectors to be substituted for alignment with the search detector. This enables the operator at remote repeater [6 to systematically allocate targets to the auxiliary detectors used in gun laying in any desired order simply by switching the connections of selector switch 21.

Referring now to Fig. 2 where generally a circuit diagram of amplifier 44 and gate multivibrator 45 are disclosed. Photoelectric cei1 43 is connected between the control grid of tube 44a and ground. Tube 44a is normally conducting. Its

cathode is positively biased due to its plate current and the current in resistors 56 and 5! flowing through the cathode resistors. The control grid is normally at a potential be1ow that of the cathode, but above cut-oi. When photoelectrc ce1l 43 is activated by the reflected 1ight beam from mirror 40, the control grid is effectively substantially grounded to cut oi tube 44a. This results in a positive trigger voltage being applied to the sereen of amplifier tube 4411 A portion of the transmitter pulse is applied at terminal 55 and hence to the grid of amplifier tube 441). The sereen of 4% is normally at or near ground potential so that practically no plate current passes through to the plate of 4412, regardless of the grid potential.

Tubes 45a and 4% of multvibrator 45 are biased by the associated resistors and p1ate voltage to be normally conducting and non-conducting, respective1y. The weak negative output pulses appearing at the p1ate of amplifier tube 44b due to the impulses received at the grid are normally of insufiicient magnitude to drive the grid of tube 45a be1ow cut-o. When the photoelectric ce11 becomes conducting however, tube 44a goes toward cut-off, applying a positive voltage to the sereen of 44b so that it conducts, amplifying the pulse applied to its grid, giving an output pulse amply large to trigger the multivibrator. The plate resistor of tube 45a is tapped and connected to the grid of a cathode follower tube 5l over path 5l. When tube 45a is cut-oi a positive pulse is impressed on the grid of cathode iollower 56. Condenser 52 then begins to charge, and the grid of tube 45a begins to rise towards the cut-ol va1ue rendering this tube once more conducting. The rate of charge and consequently the time tube 45a is cut-off is determined by the voltage at the p1ate of tube 45b during this time. This voltage is controlled by the grid bias of tube 45h during ths time. A generally variab1e group of resistors 53 in conjuncton wth potentiometer i locatec. in auxl-iary detector 3L control this grd bias. It is thus seen that after preliminary acjustment of resstor group 53 the duraton of the pcstive pu1se impressed on the grd of cathoce folower 59 is contro1led by adjustment of potentiornetcr 36 in auxiliary detector 33. The output pu1se of cathode follower 56 is connected through path 3'? to the intensifer grid of scope I8. Potentiometer provded to contro1 the brla-nce of the trace appearing on scope I due to this output pulse of cathode ol1ower 50. 'I'hs ntensfier grid is biased by another conventional blankng circuit (not shown) during the swcep perod to a va1ue sght- Iy below that required to iurninate the scope, and the output wave of cathode fcliower is suflcient to iiiuminate the trace of this scope during the occurrence of this wave. Ths illurninated trace w11 extend from the center ontwardy a dstance depending on the adustment of potentometer 36.

As long as the antennes rernan in algnment the p1ate voltage of tube 4 a wi11 reman at its upper limit, and. except for the s1ow dscharge of the coupling condenser from its plate to the sereen of tube Mb, vvil1 maintain the screen of tube 44b at a conductng leve1. Tube 45a of multvibrator 5.5 is always in the condtion to be trggered whenever the amplified transrnitter pu1se reaches its grid. I-Ience, whenever the antennas come into alignment, rectangular pu1ses are produced in synchronsm with the transmtter pulses of the search detector, and the lurninated trace wl1 appear on scope |8.

In Fig. 3 the illuminated traoe is shown as line 03. In the condtion shown the search de tector antenna is trained on a target T, and the auxlary detector antenna is aligned therewith to produce trace 013. The length OB furnishes an indicaton of the range setting of the auxiliary detector, and under the conditions shown the range setting of the auxilary detector is less than the target range by a dstance BI.

Numerous additional appicatons of the abovedsclosed prnciples wil] occur to those sklled in the art and no attempt has been made to exhaust such possiblties. The scope of the inventon is defined in the following claims.

I claim:

1. In combination, a search detector having a rotatable antenna, an auxiliary detector a1so having a rotatable antenna, a oathode ray scope for presenting data collected 'oy sad search detector, azimuth selsyns mechancally connected to each of said antennas and rotatable therewth, a differential selsyn having its rotor and stator connected respectvely to the outputs of said azimuth selsyns, a photoelectrc cel1, a mrror mounted on the shaft of said rotor and so positioned thereon to refiect a beam from a lght source on and actvate said photoelectric ce11 when the antennas of said search and auxliary detectors are algned, a gate multvibrator for producng a rectangular wave in response to activaton of said photoelectrc cel] and beng so connected to said cathode ray scope that said wave W1I appear as an illuminated trace thereon and thereby furnish an indcaton when sad antennas are algned.

2. In combinaton, a search detector having an antenna rotatable in azimuth, a cathode ray scope for presenting data collected by said search detector, handwheels or determining the azimuth and range of a target the trace of whose echo picked 1110 by sad antenna a1opears on sad cathod'e ray scope, an aux1ary detector. har'ring an antenna rotatable in azimuth and handwheels for rotating sai-d. last mentoned antenne, and setting the range searched by sad auxiliary detector, a first azimuth se1syn mechanically connected to one of said antennas and rotatabe therewith, a second azixnuth selsyn oonneeted to the other of said antennas and rotatafiole there- With, a differential selsyn havng rotor and stator respectvely connected to the outputs of sad azimuth selsyns, a photoeiectrc ce1l, a mirror mounted on the shaft of said rotor andangu-- 1ar1y positoned thereon to reflect a loeam rom lght source on and actvate said photoelectrio ce11 when the antennas of sad search and auxilary detectors are a1gned in azrnuth, a gate multivibrator for producing a reotangu- 1ar wave in response to actvation of said Photoelectric ce1l, the output of saio multivibrator being connected to the ntensfying grd of sad scope to produce an illuminated trace when said antennas are agned in azmuth, a potentiometer adjustable With the range handwheel of said auxiliary detector and so connected to sad multivbrator as to control the duration of said rectangular wave, whereby the length of the i11uminated trace on said scope Wi11 ndicate the range being searched by said auxlary detector.

3. In combination, a first search detector having a rotatable antenna, a second detector a1so having a rotatable antenna, a dfierential selsyn actuated oy said rotataole antennas, a voltage generator responsive to sad dierental se1syn,

a rnutivorator or producing a rectangular voltage pulse in response to voltages from said voltage generator, and a cathode ray tube connected to sad multivorator 0r furnishng an indicaton of alignrnent in azimuth of sad rotatable antennas.

4. In combination, first and second search detectors each having a rotatable antenna, azimuth sesyns mechanically connected to each of said antennas and rotatable therewith, a differental selsyn having its rotor and stator connected respectively to the outputs of said azimuth se1syns, means associated with the shaft of said dierental se1syn for generating a signa1 in response to azmuth alignrnent of said antennas and means for convertng said sgnal into a vsual ndcaton.

5. In combinaton, first and second search detectors each having a rotatable antenna, sad first search detector no1uding adjustable means for selectng a particular range sector, azimuth selsyns mechanically connected to each of said antennas and rotatable therewth, a dferental selsyn having its rotor and stator connected respectvely to the outputs of said azmuth selsyns, means assocated with the shaft of said difierential se1syn for generating a signa1 in response to alignment in azmuth of sad antennas, means for converting sad sgnal into a vsua1 indicaton, and means associated wth sad adjustable means of said first detector for alterng said visua1 indication to indicate the setting of said adustable means.

6. In combination, first and second search detectors each having a rotatable antenna, a cathode ray tube indicator or presentng data collected by said first search detector, azimuth se1syns mechanicaly conneoted to each of sad antennas and rotatab1e therewth, a dierential se1syn having its rotor and stator connected respectvely to the outputs of said azimuth se1syns,

a photoelectric ce1l, a mirror mounted on the shaft of said rotor and so positioned thereon to reflect a beam from a light source on said photoelectric cell in response to the azimuth alignment of sad first and second search detectors, and means associated With said photoelectric cel1 and said indicator for producing an indication on said indicator in response to the illumnation of said photoelectric ce11 by said light beam.

7. A target allocating system comprising a first pulse echo search detector havng a rotatable directional antenna, a cathode ray tube display device responsve to said detector for presenting a polar plot of al] targets withn the efiectve search area of said detector, a second pulse echo search detector remote from said first detector and having a directional antenna, means for rotatng said second antenna, means for indicating on said display device azimuth alignment REFERENCES CI'IED The following references are of record in the file of this patent:

UNITED STATES PA'I'ENTS Number Name Date 2231,929 Lyman Feb. 18, 1941 2312,203 Wallace Feb. 23, 1943 2,463,476 Busignies Mar. 1, 1949 2,510,692 Goddard June 6, 1950 2537,102 Stokes Jan. 9, 1951 

